A test client for simulating HTTP requests during testing without
requiring running a server.

Werkzeug is Unicode aware and doesn’t enforce any dependencies. It is up
to the developer to choose a template engine, database adapter, and even
how to handle requests. It can be used to build all sorts of end user
applications such as blogs, wikis, or bulletin boards.

Flask wraps Werkzeug, using it to handle the details of WSGI while
providing more structure and patterns for defining powerful
applications.